Error in querying view

Hi

I don't know whether this has been fixed in 6.4 -- I still cannot get
6.4 to compile and run on Alpha -- but I have the following error when
querying a view in 6.3.2:

I have a table with jobs/tasks (one job can consist of several tasks)
that need to be executed, and have created a relatively complicated view
(tasks_todo) on this table, which gives me all jobs that are finished.
When I then try to create the following very simple view, I get an
error:

cb=> create view jobs_done as select j.job from jobs j where not j.job
in (select job from tasks_todo);
CREATE
cb=> select * from jobs_done;
ERROR: ExecEvalExpr: unknown expression type 108
cb=> select * from tasks_todo;
job|task|priority|joblink|state
---+----+--------+-------+-----
58| 58| 3| 0| 4
67| 67| 3| 0| 4
44| 44| 3| 0| 4
61| 61| 3| 0| 4
70| 70| 5| 0| 4
88| 96| 3| 80| 2
89| 97| 3| 76| 0
90| 98| 3| 77| 0
91| 99| 3| 78| 0
92| 100| 3| 79| 0
95| 103| 3| 82| 0
93| 101| 3| 80| 0
96| 104| 3| 80| 2
100| 108| 3| 81| 0
112| 120| 3| 101| 0
113| 121| 3| 73| 0
111| 119| 3| 74| 0
(17 rows)

cb=> select j.job from jobs j where not j.job in (select job from
tasks_todo);
job
---
55
57
59
60
42
56
74
75
77
78
79
80
81
73
86
85
87
76
101
82
(20 rows)

So, is there a problem with using NOT..IN.. in a view?

Any help appreciated,

Adriaan